A wide variety of fastening elements are available for securing items to walls and other surfaces. Such fasteners include common nails, self-tapping screws, machine screws, plastic screw anchors (used in plaster board and the like), lead screw anchors (used in masonry), hollow wall anchors, masonry screws, and cotter pins. In certain applications, a fastener of a desired diameter is required; however, this diameter is rarely if ever printed on the fastening element. If many sizes of fastening elements are available, it can be a slow and tedious process to select a fastener having the correct size for a particular application. Often, calipers are required to perform accurate measurements.
The guess work and delay associated with selecting a correctly sized fastening element are increased when a drill bit is required to form or drill a hole for engageably receiving the fastening element. It may be difficult, if not impossible, to determine the appropriate drill bit size that corresponds to a particular fastening element. Even when written instructions call for a specific drill bit diameter or the user has a chart of corresponding fastener and drill bit sizes, proper selection and matching may be complicated if the sizes are not printed clearly on the drill bits. In many cases, drill bit diameters are unclear, obliterated, or all together missing from the bit. As a result, the user is reduced to "eye-balling" the fasteners and drill bits and must guess the correct sizes. Alternatively, the user may again be forced to use time consuming and tedious measuring tools such as calipers.
Selecting the proper fastener is important; selecting a drill bit that corresponds to a particular fastener is required so that the fastener exerts its optimal holding power. Furthermore, a screw inserted in an improperly sized hole may cause damage to the surface.